This invention relates to a plate-type separator. More particularly this invention relates to a plate-type fluid separator and a method of using same for separating two or more immiscible components from a fluid mixture thereof.
With environmental concerns on the rise, the development of improved means for separating immiscible components from mixtures thereof remains an important goal in modern society. The separation of immiscible components from fluid mixtures thereof has made it possible, for example, to recycle waste into useful materials, thus reducing the need for new landfills, which zoning regulations and neighborhood concerns have made difficult to find. Furthermore, the separation of such immiscible pollutants as oil particles from aqueous solutions thereof has reduced the pollution of streams, lakes, wells, and the like, with runoff or drainage discharge water contaminated with the immiscible oil particles. As concern for the environment grows in this country, various states as well as the federal government have imposed regulations governing the quality of such effluent water.
Plate-type separators and methods of using same for separating immiscible fluids from mixtures thereof are known in the art. Reference is made, for example, to U.S. Pat. Nos. 4,554,074 to Broughton; 5,266,191 to Greene et al.; and 5,039,426 to Giddings. However, as will be discussed hereinbelow, the separators and separation processes described in these references have drawbacks.
Broughton discloses a separator for separating high density and low density fluids, wherein the separator contains top and bottom support plates and an inlet fluid channel branched into multiple dual channels which convert the inlet channel turbulent fluid flow into a substantially laminar fluid flow. In Broughton, the portions become distinct within the branched structure but are separated after the stream exits the branched structure, separation being achieved by means of a funnel. Thus, in Broughton, the branched structure is not used to achieve the separation itself but to reduce the flow rate of the divided streams to result in laminar flow and the formation of distinct portions within the channels.
Greene et al. is directed to a separator for separating fluids having different buoyancies, wherein the separator is composed of a separator chamber having a plurality of parallel subchannels formed by spaced vertical plates. The subchannels in the Greene et al. separator have a geometry which reduces and controls the Reynolds number of the subchannels and controls the velocity through the subchannels, causing the flow to be substantially non-turbulent.
Giddings discloses a process for continuous particle and polymer separation wherein a stream of carrier fluid containing the material to be separated is injected into the inlet end of a thin channel and the flow rate is adjusted to a sufficiently high level such that flow-dependent lift forces the different components to different transverse positions by the time they reach the end of the channel. Outlet flow is split into at least two substreams by means of physical splitters, with the flowrates of the multiple substreams being adjusted such that the transverse position of the outlet splitting plane divides the particles into enriched phases, which are then collected from emerging outlet streams. The separation process taught in Giddings can achieve a high degree of efficiency in a single separation chamber by manipulating the flow rate through the chamber. Separation according to the Giddings method relies on lift forces which, as Giddings expressly teaches, are flow rate-dependent forces arising as a result of fluid motion. Giddings distinguishes lift forces from viscous and gravitational forces, which are not dependent on flowrate.
As stated hereinabove, the separators and separation methods disclosed in the references discussed above have several drawbacks. For example, the separator in each reference is designed to separate components according to density (i.e., buoyancy) differences. None of the references discloses a separator which can separate components differing in viscosity values. In particular, none of the references teach a single separator which is capable of separating components differing in density values and components differing in viscosity values. It would be desirable to provide a separator which can separate immiscible components differing in viscosity values as well as immiscible components differing in density values.
Another drawback to the separators and separation processes disclosed in the foregoing references is that separation in each of the references is dependent on flow rate. For example, the separation processes taught in Broughton and Greene et al. both require non-turbulent, substantially laminar flow; and the separation process taught in Giddings relies on lift forces, which are flow rate-dependent. It would be desirable to provide a separator which can effect separation of immiscible components regardless of the flow rate and regardless of whether the flow is turbulent or non-turbulent.
Broughton further has the disadvantage of requiring additional equipment, i.e., the funnel, and additional process steps, i.e., use of the funnel, to effect separation of immiscible components. In Broughton, separation does not occur in the branched structure but outside the branched structure, specifically, in the funnel. It would be desirable to provide a separator wherein the portions are mutually separated within the branched structure so as to eliminate the need for extra equipment and extra process steps.
Furthermore, none of the references disclose a separator wherein complete separation of the immiscible components is carried out on a single surface of a plate. As stated hereinabove, Broughton uses a funnel to separate the component portions from one another. The separators disclosed in Greene et al. and Giddings both require a plurality of spaced plates, the spaces between the plates themselves forming the requisite flow channels. It would be further desirable to provide a separator which can effect separation using only one plate. It would also be desirable to provide a separator which can effect separation using a single surface of a single plate.
In addition to the disadvantages described above, many conventional plate-type separators are also undesirably bulky, which increases the expense associated with making, cleaning, re-using and replacing the separators. For example, many conventional separators contain thick metal plates which, because of their thickness, are expensive to accurately drill, ream or otherwise machine. Moreover, with use, the separator must be periodically cleaned as material tends to solidify and collect within the separator's flow channels, which must be periodically cleaned and then inspected to ensure that the cleaning process has effectively removed all of the collected material. The small size of the flow channels renders the inspection process tedious and time-consuming and, therefore, imparts a considerable cost to the overall cleaning/inspection process. The high initial cost of the thick metal plates precludes discarding or disposing of the plates as an alternative to cleaning. Therefore, it would be desirable to provide a separator which is less bulky. In addition, linking a plurality of separation chambers in such separators will dramatically increase the cost of the separator, with two serially linked separation chambers typically costing twice as much as a single chamber, and a thousand serially linked separation chambers costing a thousand times more than a single separation chamber.
Accordingly, it is a primary object of this invention to provide a separator which can separate immiscible components differing in viscosity values as well as immiscible components differing in density values.
It is another object of this invention to provide a separator composed of a branched structure wherein separation occurs within the branched structure.
It is another object of this invention to provide a separator which effects separation using only one plate.
It is a further object of this invention to provide a separator which affects separation using a single surface of a single plate.
An additional object of this invention is to provide a separator which is less bulky and less expensive to make, inspect, clean, re-use or replace.
A further object of this invention is to provide a method of separating immiscible components from a fluid mixture thereof wherein the method involves the use of a plate-type separator having the characteristics set forth in the preceding objects.
These and other objects which are achieved according to the present invention can be readily discerned from the following description.